Implantable neurostimulation systems have proven therapeutic in a wide variety of diseases and disorders. Pacemakers and Implantable Cardiac Defibrillators (ICDs) have proven highly effective in the treatment of a number of cardiac conditions (e.g., arrhythmias). Spinal Cord Stimulation (SCS) systems have long been accepted as a therapeutic modality for the treatment of chronic pain syndromes, and the application of tissue stimulation has begun to expand to additional applications, such as angina pectoris and incontinence. Further, in recent investigations, Peripheral Nerve Stimulation (PNS) systems have demonstrated efficacy in the treatment of chronic pain syndromes and incontinence, and a number of additional applications are currently under investigation.
More pertinent to the present inventions described herein, Deep Brain Stimulation (DBS) has been applied therapeutically for well over a decade for the treatment of neurological disorders, including Parkinson's Disease, essential tremor, dystonia, and epilepsy, to name but a few. Further details discussing the treatment of diseases using DBS are disclosed in U.S. Pat. Nos. 6,845,267, and 6,950,707, which are expressly incorporated herein by reference.
Each of these implantable neurostimulation systems typically includes one or more electrode carrying stimulation leads, which are implanted at the desired stimulation site, and a neurostimulator implanted remotely from the stimulation site, but coupled either directly to the neurostimulation lead(s) or indirectly to the neurostimulation lead(s) via a lead extension. The neurostimulation system may further comprise a handheld external control device to remotely instruct the neurostimulator to generate electrical stimulation pulses in accordance with selected stimulation parameters. Typically, the stimulation parameters programmed into the neurostimulator can be adjusted by manipulating controls on the external control device to modify the electrical stimulation provided by the neurostimulator system to the patient.
Thus, in accordance with the stimulation parameters programmed by the external control device, electrical pulses can be delivered from the neurostimulator to the stimulation electrode(s) to stimulate or activate a volume of tissue in accordance with a set of stimulation parameters and provide the desired efficacious therapy to the patient. The best stimulation parameter set will typically be one that delivers stimulation energy to the volume of tissue that must be stimulated in order to provide the therapeutic benefit (e.g., treatment of movement disorders), while minimizing the volume of non-target tissue that is stimulated. A typical stimulation parameter set may include the electrodes that are acting as anodes or cathodes, as well as the amplitude, duration, and rate of the stimulation pulses.
Programming a neurostimulator (e.g., a DBS stimulator for treating movement disorders) can be a laborious and time intensive process that can take many programming sessions over several months to complete. In the context of DBS, neurostimulation leads with a complex arrangement of electrodes that not only are distributed axially along the leads, but are also distributed circumferentially around the neurostimulation leads as segmented electrodes, can be used. The large number of electrodes available, combined with the ability to generate a variety of complex stimulation pulses, presents a huge selection of stimulation parameter sets to the clinician or patient.
To facilitate such selection, the clinician generally programs the external control device, and if applicable the neurostimulator, through a computerized programming system. This programming system can be a self-contained hardware/software system, or can be defined predominantly by software running on a standard personal computer (PC). The PC or custom hardware may actively control the characteristics of the electrical stimulation generated by the neurostimulator to allow the optimum stimulation parameters to be determined based on patient feedback and to subsequently program the external control device with the optimum stimulation parameters.
To facilitate determination of the location of the electrodes relative to the target tissue region or regions, and even the non-target tissue region or regions, the computerized programming system may optionally be capable of storing one or more anatomical regions of interest, which may be registered with the neurostimulation leads when implanted with the patient. The anatomical region of interest may be obtained from a generally available atlas, and in the case of DBS, a brain atlas. Although the use of a generalized brain atlas may be quite helpful when optimizing the stimulation parameters that are ultimately programmed into the neurostimulation system, these types of atlases are not patient specific, and thus, cannot account for patient specific physiology.
After the DBS system has been implanted and fitted, post-implant programming sessions are typically required if the treatment provided by the implanted DBS system is no longer effective or otherwise is not therapeutically or operationally optimum due to, e.g., disease progression, motor re-learning, or other changes. As physicians and clinicians become more comfortable with implanting neurostimulation systems and time in the operating room decreases, post-implant programming sessions are becoming a larger portion of the process.
Regardless of the skill of the physician or clinician, neurostimulation programming sessions can be especially lengthy when programming complicated neurostimulation systems, such as DBS systems, where patients usually cannot feel the effects of stimulation, and the effects of the stimulation may be difficult to observe, are typically subjective, or otherwise may take a long time to become apparent. Clinical estimates suggest that 18-36 hours per patient are necessary to program and assess DBS patients with current techniques (see Hunka K., et al., Nursing Time to Program and Assess Deep Brain Stimulators in Movement Disorder Patients, J. Neursci Nurs. 37: 204-10), which is an extremely large time commitment for both the physician/clinician and the patient.
Recent advances in DBS programming systems include the ability to predict and visualize the stimulation field based on the position of the lead in the anatomy and the electrode configuration. The anatomy is scaled to map to the patient's brain via a process called “registration.” Registration involves using the pre-op MR images and post-op CT images of a patient, and generating a “transformation” data set that enables the scaling of a generic 3D brain atlas to represent the specific patient's brain. In addition to the transformation data set, additional information such as the lead data (model, electrodes size/shape/position, connections to the stimulator, orientation of the lead in the brain, etc.) are key to predicting the stimulation field.
It can be appreciated from this that the availability of patient-specific data (e.g., a patient-specific 3D atlas, a lead orientation relative to the patient's tissue, imaging data for the patient, and clinical effects for the patient) has a significant impact on the complexity of, and the amount of time required for, programming a neurostimulator. This patient-specific data may be readily available during implantation of the neurostimulator and is stored within the computerized programming system used during neurostimulator implantation in the operating room. However, once implanted, subsequent programming of the neurostimulator may be impacted by the availability of this patient-specific data. Because the patient-specific data is only stored in the computerized programming system used in the operating room, this same computerized programming system must be used during the navigation session or follow-up reprogramming session, or the patient-specific data must be transferred from the operating room computerized programming system to the new computerized programming system. However, in a clinical setting, it is quite common that the same computerized programming system is not available to program the neurostimulator, and there is a high likelihood that the neurostimulator is programmed or reprogrammed using a different computerized programming system (either in the same hospital/clinic or in a different hospital/clinic).
Significantly contributing to the lengthy process of programming a neurostimulation system is the fact that patient-specific data may not be available during a programming session. Thus, there remains a need for an improved neurostimulator system that allows an external control device to program a neurostimulator implanted within a patient without having prior knowledge of patient-specific data.